DESCRIPTION: (from the applicant's abstract) The objective of the proposed research is an evaluation of how and how well the binaural auditory system processes certain interaural temporal disparities (ITDs) and certain interaural intensitive disparities (IIDs). The experiments proposed are focused on two general topics: 1) the ability of the binaural auditory system to utilize dynamically- varying interaural information, a topic sometimes referred to in the literature as 'binaural sluggishness' (Aim1); 2) an investigation of how binaural interference is affected by details concerning the temporal properties of interferers and targets (Aim 2). The overall goal is to extend greatly the knowledge of how the human's ability to detect and to discriminate interaural disparities is affected by the spectral region and spectral compositions of sounds that are processed via binaural interactions. One large subset of experiments will focus on how sensitive listeners are to abrupt changes in the magnitude of interaural cues. The experiments have been designed to yield a quantitative assessment of the listeners' behavior including the derivation of time-constants that describe performance. A second set of experiments concerns the measurement of 'binaural interference' produced by spectrally remote stimuli in detection and lateralization paradigms. The experiments can be characterized as a systematic and parametric investigation of how binaural interference is affected by details concerning the temporal properties of interferers and targets. Beyond providing fundamental data concerning binaural processing of high-frequency signals in the presence of potentially conflicting low-frequency information, the parametric experiments should yield substantial insight into the mechanism or mechanisms that underlie interference phenomena. The potential health benefits are a better understanding of how the ear and brain process information and the potential for 'better' diagnostic procedures that may, eventually, have clinical significance.